The Vedas are synonymous to the knowledge used for the benefit of human kind. According to the tradition of the Rishis of Bharat (lndia), the root source of this knowledge is The Omniscient God. Due entirely to His grace, at the beginning of creation, the four Vedas, viz. Rigveda, Yajurveda, Samaveda, and Atharvaveda came into light through the rishis, Agni, Vayu Rishi, Aditya and Angirah, respectively. This happened when there existed no mode of verbal communication. Accordingly Vedas are the origin of the Sanskrit and other languages. Also, they are the source of scientific knowledge.
The Vedas contain teachings related to Dharma, Artha, Kama and Moksha for the welfare of human kind. These four elements are also the sources of Spiritual, Mental, Physical and Social development. In Vedas, we find the descriptions of the micro and the macro world as well as the knowledge of the Soul and the Supreme Reality. They also teach the methods of achieving the ultimate happiness by devotion to the Almighty. The Rigveda presents us with the following beautiful hymn to spread this wonderful knowledge throughout the world:
Om Indram vardhanto apturah krinvanto vishwamaryam.
(Rigveda - 9/63/5)
Meaning, the humans must enhance the 'Indra' i.e. the soul, the prosperity and the good deeds, removing their attitudes of misery and the evils. This not only helps us improve our own lives but also helps us contribute towards the betterment of others. This was the main reason why Maharshi Dayananda Saraswati declared "Krinvanto Vishwamaryam" as the motto for Arya Samaj.
Here, the word "Arya" does not refer to any particular 'race', 'cast' or 'creed'; rather, it means a virtuous person. As it has been said:
Kartavyamacharn Karma, Akratvyamanacharan.
Vishthti Prakritachare yeh sa Arya smriteh
Meaning, a person who does only praiseworthy acts, holds the traditions in high regard and upholds them, does not adopt harmful habits and actions, but instead gets rid of such, and is, by his or her nature, a caring person, is alone called Arya.